The St. Louis Motor is an open DC-operated motor with all the parts visible and adjustable. There are a few different types of St. Louis motor available. Ours is from Arbor Scientific, and is made to be operated at a potential of 6 volts continuously or up to 8V for short periods of time.
To Setup:
Adjust the metal brushes (the contacts that touch the rotor) so that they are gently touching the copper contacts on the rotor.
Slide the two permanent magnets into the slots on either side of the rotor.
Wire three D-Cell batteries (3x1.5V = 4.5V) and a switch in series. You can use the components of the Magnetism and Electricity kit for this.
Note: you can get the motor to work with as few as one battery, but only if it is aligned just right. Start with three batteries.
More than 5 batteries is not recommended, as the motor is not rated for more than 8 volts. (5 x 1.5 volts = 7.5 volts).
Wire the battery/switch assembly (with the switch OPEN) to the posts on top of the motor.
To Run:
Turn the rotor so that it is perpendicular to the magnets.
Close the switch. The motor should begin to spin.
If the motor does not spin, or spins only slowly, troubleshoot by adjusting the components.
Sample Investigations:
How does the number of batteries affect the speed of the motor?
How does the wiring of the batteries (series vs. parallel) affect the motor?
Can you get the motor to spin in the opposite direction?
To Setup:
To Run:
Sample Investigations: